Finding Tractable Formulas in NNF. - Edgar Altamirano; Gonzalo Escalada-Imaz (Computational Logic, 2000)

An Efficient Proof Method for Non-clausal Reasoning. - Edgar Altamirano; Gonzalo Escalada-Imaz (ISMIS, 2000)

Extending Polynomiality to a Class of Non-clausal Many-Valued Horn-Like Formulas. - Edgar Altamirano; Gonzalo Escalada-Imaz (ECSQARU, 2001)